After a 12% decline in the number of keratoplasties in the U.S. between 2004 and 2006 there has been a 37% increase in the number of keratoplasties in just two years. As with the Cornea Donor Study (CDS) 10 years ago, an important public health issue is again raised regarding the future adequacy of the donor pool. This recent increase has been largely driven by the advent of endothelial keratoplasty procedures which have nearly tripled, representing 33% of the keratoplasties in 2008. Coupled with a higher failure rate in the initial postoperative period than penetrating keratoplasty, an aging population with a greater number of endothelial dysfunction cases, and potential changes in the cornea evaluation process with increased regulations and more extensive laboratory testing requirements to test for emerging infections, other means to expand the donor pool besides the use of older donor tissue are needed to guarantee future supply. One major opportunity is to extend the use of donor tissue to the full FDA approved preservation time of 14 days for intermediate storage media at 40C. Corneas preserved beyond 7 days are rarely used for transplantation in the U.S. but are often exported for successful international use. While existing data do not support this bias, an evidence-based study is needed to change this practice pattern. Thus, our primary objective is to determine whether graft clarity and endothelial cell loss, the two most recognized measures of endothelial keratoplasty success, are comparable three years postoperatively for donor corneas preserved up to 7 days vs. those preserved from 8 to 14 days prior to surgery utilizing a randomized, prospective, masked clinical trial. Two separate grant applications have been submitted. The Data Management and Analysis Center (DMAC) at the Jaeb Center for Health Research, which directed the CDS, will oversee all aspects of eye bank participation in the study, multi-functional website development, data management, statistical analysis, and DSMC coordination. The Coordinating Center at Case Western Reserve University and University Hospitals Eye Institute, directed by the Study Chair, will provide scientific direction and coordination of the clinical sites and Cornea Image Analysis Reading Center activities.